Glad to hear there's a lot of interest in this!
I think file triggers would definitely help with optimizing containerization, but I think
it still has some issues. Two properties that would be desirable for optimizing
containerization are:
1. Mergeability. If multiple packages perform the same task, it can just be run once.
2. Equivalence of incremental changes and a clean build (or anti-hysteresis; see
https://blog.verbum.org/2020/08/22/immutable-%E2%86%92-reprovisionable-an...).
If different systems install (or uninstall) the same packages in a different order, is the
final state guaranteed to be identical?
I think transactional file triggers help with 1, but I don't think they currently
guarantee 2. I'm wondering if there'd be any way to allow RPMs to guarantee 2.